Manufacture of hollow artificial threads



Patented July 8, 1930 UNITED STATES HANS KARPLUS, OFFRANKFORT-ON-THE-MAIN, GERMANY MANUFACTURE OF HOLLOW ARTIFICIAL THREADSNo Drawing. Application filed December 9, 1927, Serial No. 239,005, andin Czechoslovakia December state of fine division. only during thepr0cess of spinning. In any case, the substances incorporated aresubsequently eliminated again from the textile threads by means ofsuitable solvents, so that the place of the incorporated substances istaken by uniformly and exceedingly finely distributed bubbles, and inthis way are obtained hollow threads of great softness and of small heatconductivity.

New experiments have shown that the subsequent removal or elimlnation ofthe incorporated substances may also be obtained in an advantageousmanner by the action of a vacuum, so that the process is thusconsiderably cheapened owing to the saving of the otherwise requiredsolvent. If the substances incorporated have a high boiling point, it isnecessary to expose the textile threads to the action of a vacuum at ahigher temperature. As is well known, the lowering of the boilingtemperature in the case of the decrease of the outer pressure to one andthe same amount, is much smaller in the case of higher pressures than inthe case of low pressures, from which it follows that the action of areduction of pressure at pressures already low in themselves, is quiteextraordinarily large.

If for instance a petroleum fraction or some other hydrocarbon with aboiling point 200 has been incorporated, the boiling point at a pressureof 660 mm. mercury column will still be about 130, on the contrary at apressure of 20 mm. it will be only 8090,.at a

pressure of 10 mm., about 75. With the assistance of a very high vacuum,it is therefore possible to reduce the temperature of distillation evenof substances with a high boiling point, for instance oils, to quite anextraordinary extent, and even substances which volatilize withdifficulty, may be completely eliminated again from the textile threads,hollow spaces being formed, whilst in the case of easily volatilesubstances, this may be done with the assistance of a vacuum, withoutany heating.

I claim:

1. A process for the manufacture of porous artificial textile filamentsfrom spinning solutions such as viscose, ammoniacal copper oxide,cellulose acetate, and Intro-cellulose solutions, and in which solutionsthere are incorporated normally non-volatile substances which during thesecond process of spinning and finishing of the filaments, do notgenerate any bubbles forming vapors or gases, which process includes thestep of removing the incorporated substances by subjecting the filamentsto vacuum, whereby to effect the evapo ration of the incorporatedsubstances and to leave, void, the porous spaces previously occupied bythe substances.

2. A process for the manufacture of porous artificial textile filamentsfrom spinning solutions such as viscose, ammoniacal copper oxide,cellulose acetate, and nitro-cellulose solutions, and in which solutionsthere are incorporated substances such as petroleum fractions or otherhydrocarbons possessing a high boiling point and, therefore, normallynon-volatile, which process includes the stepof removing theincorporated substances by subjecting the filaments to heat and vacuumwhereby to effect evaporation of the incorporated substances and toleave, void,-the porous spaces previously occupied by the substances.

3. A process for the manufacture of porous artificial textile filamentsfrom spinning solutions such as viscose, ammoniacal copper oxide,cellulose acetate, and nitro-cellulose solutions, and in which solutionsthere are incorporated substances such as petroleum fractions or otherhydrocarbons possessin a high boiling point and, therefore, norma ynonvolatile, which process includes the step of removing theincorporated substances by subjecting the filaments to heat and vacuumwhereby to efiect vacuum of the incorporated substances and to leave,void, the porous spaces previously occupied by the substances, the deree of vacuum eing the inverse ratio to the boiling point of thesubstances.

In testimony whereof I afiix my si nature.

HANS KARP US.

